One example of known elastic yarn feeding devices of the circular knitting machine is disclosed in Japanese Utility Model Examined Publication No. 59(1984)-2051. In the elastic yarn feeding device disclosed in this publication, a feed roller is urged against the upper surface of a horizontal rotary plate which is driven by a drive, and the feed roller is rotated by the rotation of the rotary plate. An elastic yarn (rubber yarn) is passed between the rotary plate and the feed roller so as to be held between them, and the elastic yarn is fed to the circular knitting machine by the rotation of the feed roller. The feed speed of the elastic yarn is changed by moving the feed roller in a radial direction of the rotary plate. As the feed roller is moved radially outwardly of the rotary plate, the circumferential speed of the rotary plate is increased and hence so does the rotational speed of the feed roller.
This known elastic yarn feeding device can feed only one elastic yarn and cannot be used without modification for a multi-yarn feeding device which is used for knitting stretchable knitted products such as body suits and hose. Moreover, use of this elastic yarn feeding device to feed elastic yarns requires a plurality of such elastic yarn feeding devices, and thus the whole system involves problems such that it becomes large sized, and requires a large occupying area and complicated rigging.
It is an object of the present invention to provide an elastic yarn feeding device suitable for multi-yarn feeding circular knitting machines. The elastic yarn feeding device is capable of feeding elastic yarns simultaneously and at the same speed and is small in overall size with a simple structure. In addition, the elastic yarn feeding device is capable of stopping the feeding of any one of the elastic yarns.